Existing research indicates that the impressions that people form about one another are comprised of both episodic and categorical memory representations. Episodic memory refers to memory for specific events, while categorical memory refers to higher-order concepts abstracted from episodic information. This grant proposes a series of studies to investigate the role that each of these types of memory plays in a determining the persistence of an established person impression. A multiple judgment task is introduced that makes it possible to distinguish whether subjects are relying on categorical or episodic memory representations when they make paired-comparison likeability judgment about described stimulus persons. Conjointly, an Episodic-Categorical model of memory-based impression judgements is presented capable of accounting for subjects' choice behavior. Five studies are proposed that would make it possible to extend the model to account for impression change by identifying the degree to which the persistence of an established impression depends on episodic memory, categorical memory, and memory for previous decisions that have been made about a person. Development of the theoretical model is seen as having important significance for a variety of cognitive tasks, including estimates of event frequency, stereotyping, and medical diagnosis.